The best thing about the Android is the endless customization it provides. From home screen, widgets, icon packs to the Custom ROM you can change every little thing in Android. One of the most popular thing on Android is to change the theme from light to dark. Thanks to the Android 8.1, You can change the Theme of your device.
Android 8.1 introduced the feature so when you set dark wallpaper it automatically sets a dark theme and when you set light wallpaper it sets light theme automatically. So now the only thing you need is to set light wallpaper in morning and set dark wallpaper in the night.
Download Smart Wallpaper
Smart Launcher is an app that changes your wallpapers based on time, day or month. You can also change wallpaper on sunset and sunrise. This app is available on play store for free.
Once you install this application just set it up and allow all the permissions it asks. It might ask permissions like storage and location, so just allow it.
Enable Different Wallpapers for Night
Now go to the setting option enable the different wallpapers at night and choose the wallpaper you want to set.
So, Now wallpaper will change for the day and night time so with that the theme of your android will change automatically according to your wallpaper.
The weather-based method is not the only option available in Smart Wallpaper. You can implement the same day/night change using a day of the week or month of the year. If you would rather use one of these methods, follow the same steps as above from within the appropriate menu in Smart Wallpaper (day or month).